问题 解答题
计算下面各题,能简算的要简算
7
15
+
13
18
+
8
15
1-
1
2
-
1
5
5
9
+
2
3
-
4
9
答案

(1)

7
15
+
13
18
+
8
15

=

7
15
+
8
15
+
13
18

=1+

13
18

=1

13
18

(2)1-

1
2
-
1
5

=

1
2
-
1
5

=

3
10

(3)

5
9
+
2
3
-
4
9

=

5
9
-
4
9
+
2
3

=

1
9
+
2
3

=

7
9

判断题
计算题